The present disclosure relates to medical systems, devices, and methods, particularly for the treatment of atrial fibrillation (AF). AF is by far the most common arrhythmic heart disorder in the United States. AF may affects some 2 million people and can account for some 500,000 hospital admissions a year. AF can increase the risk of stroke by some 5-fold and can lead to almost 80,000 deaths annually. While most patients with AF can be managed adequately with conservative medical therapy, a large number of patients can develop complications to the medicines used to treat the disease including fatigue, lightheadedness, or substantial bleeding. Furthermore, a substantial number of patients may be unable to tolerate AF due to disabling symptoms. Drugs that are used to prevent AF may not be very effective and can have potentially serious long term complications. While open surgical approaches like the Cox-Maze procedure may be shown to be quite effective in treating the disorder, less invasive catheter-based techniques may be successful only about 60% of the time. Given the enormous number of these procedures, even a modest improvement in therapeutic outcomes can have a large public-health impact.
Catheter ablation has had enormous success in the treatment of many heart rhythm disturbances. A well-placed destruction of the conductive property of cardiac tissue may interrupt the abnormal conduction pathway which may be the basis for essentially all heart arrhythmia. While catheter ablation may be highly successful in the treatment of conditions where the offending conduction disturbance is well known and localized, such as accessory conduction pathways or atrial flutter, its success in treating the most common arrhythmia of AF has been modest. The procedure can require several hours of anesthesia, radiation, and the use of multiple catheters with their attendant risks even in the hands of skilled operators. There are therefore needs for an ablation catheter that simplifies the mechanics of the creation of the contiguous electrical-isolation lines in the ablation procedure. Such an improved ablation catheter may increase the success rate of the procedure for patients while greatly reducing the associated cost of these procedures. There are also needs for self-navigating catheter apparatuses and systems that can provide a robust ablation system to greatly simplify the invasive treatment of atrial fibrillation.
AF is one of the most common cardiovascular disorders in the developed world. AF can be prevalent (e.g., about 10% of the population over the age of 70 may be afflicted), can cause up to ⅓ of all strokes, and may respond only modestly to medications. While much of the risk of AF's most feared consequence, stroke, can be reduced with long-term blood-thinner treatments, substantial morbidity and mortality may still exist. Because of the potential complications for long term anticoagulation and because a substantial degree of morbidity in patients may be symptomatic, the ablation of atrial fibrillation is one of the most practiced intracardiac procedures. However, current percutaneous therapy for AF may not have the success rate sufficient to be attempted in most AF patients. Even in carefully selected patients, the success rate may only be 60-70%. Recently the direct visualization of atrial “rotors” has been developed. While many are cautiously hopeful, the impact of such development on the success of AF ablation may remain unknown. In contrast, the surgical treatment of atrial fibrillation using the modified Cox-Maze procedure is successful in greater than 90% of patients. The surgical success suggests that the shortcomings of percutaneous approaches to AF ablation may be due to solvable technical hurdles.
The greater space and freedom of intracardiac interventions may complicate both ablation target identification and device control, which may make the procedures complex, time-consuming, and less successful. There are therefore needs for ablation catheter apparatuses which are self-navigating such that a complete pulmonary vein isolation procedure can be performed in less than one hour.
The standard ablation AF target may be based on anatomic isolation of the pulmonary veins. Promising recent data generated in relation to embodiments of the present disclosure suggest that a physiologic approach of identifying “rotors” sources in AF may also be important. The ablation of identified AF ablation targets may be suboptimal due to the difficulty of accurate catheter placement for contiguous ablations and monitoring treatment.
The following references may be of interest: U.S. Patent Application Publication Nos. 2007/0270686, 2009/0312755, 2010/0049099, 2010/0168620, 2010/0191232, 2011/0184406, 2012/0184953, and 2013/0116688; and U.S. Pat. Nos. 6,272,371, 7,008,418, 7,097,643, 8,048,063, and 8,657,815.